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Abstract:

One embodiment may take the form of a method of reducing noise from
vibration of a device on a hard surface. The method includes activating a
haptic device to indicate an alert and sensing an audible level during
activation of the haptic device. Additionally, the method includes
determining if the audible level exceeds a threshold and initiating
mitigation routines to reduce the audible level to a level below the
threshold if the threshold is exceeded.

Claims:

1. A method of reducing noise from vibration of a device on a hard
surface, the method comprising: activating a haptic device to indicate an
alert; sensing an audible level during activation of the haptic device;
determining if the audible level exceeds a threshold using a processor;
and initiating mitigation routines to reduce the audible level to a level
below the threshold, if the threshold is exceeded.

2. The method of claim 1 wherein the threshold level corresponds to a
volume level setting for an audible alert.

3. The method of claim 1 wherein the threshold level corresponds to a
noise level expected when the device is located on a hard surface.

4. The method of claim 1 further comprising: sensing an audible level
prior to activation of the haptic device; and comparing the audible
levels of prior to activation of the haptic device to the audible level
during activation of the haptic device to determine a change in audible
level.

5. The method of claim 1 wherein initiating mitigation routines comprises
at least one of reducing the speed of the haptic device, reducing the
frequency of the haptic device, reducing the amplitude of the haptic
device, gradually increasing the speed of the haptic device, and stopping
the haptic device.

6. The method of claim 1 wherein a plurality of thresholds are provided
and wherein further the initiation of a particular mitigation routine
corresponds with exceeding a particular threshold.

7. The method of claim 1 further comprising actuating at least one of a
visual or audible alert.

8. A method of mitigating locomotion of a device due to haptic devices,
the method comprising: activating a haptic device; sensing movement of
the device when the haptic device is activated; determining, using a
processor, if the movement is due to the haptic device activation; and
initiating mitigation routines to reduce the movement of the device due
to activation of the haptic device.

9. The method of claim 8 further comprising: determining if the movement
exceeds a threshold, if the movement is due to the haptic device
activation; and only initiating mitigation routines if the threshold is
exceeded.

10. The method of claim 8 wherein determining if the movement is due to
activation of the haptic device comprises determining if the movement
exceeds a threshold distance.

11. The method of claim 8 further comprising: determining an orientation
of the device; and based on the orientation determination, determining if
the device is at risk of locomotion.

12. The method of claim 8 further comprising: determining if the device
is near an edge; and stopping the haptic device if the device is near the
edge.

13. The method of claim 12 further comprising activating an edge alert if
the device is near the edge.

14. The method of claim 8 wherein the mitigation routines comprise at
least one of stopping the haptic device; slowing the haptic device,
ramping up the haptic device; and reversing direction of operation for
the haptic device.

15. The method of claim 8 further comprising actuating at least one of a
visual or audible alert if the movement is due to actuation of the haptic
device.

16. A method of reducing reverberation of a linear vibrator in an
electronic device, the method comprising: sensing movement of the linear
vibrator; determining if the linear vibrator is activated; providing
feedback signals via a feedback control system if the linear vibrator is
not activated, the feedback signals reducing the movement of the linear
vibrator.

17. The method of claim 16 wherein sensing movement of the linear
vibrator comprises sensing back electromagnetic force (EMF) induced by
movement of a magnet of the linear vibrator.

18. The method of claim 17 wherein the feedback signal corresponds in
amplitude with the sensed EMF.

19. The method of claim 17 wherein the movement of the linear vibrator is
sensed by an accelerometer and wherein further the feedback signal is
generated based on the signals from the accelerometer.

20. The method of claim 17 wherein the feedback signal is out of phase
with the sensed movement of the linear vibrator.

21. A portable electronic device comprising: at least one haptic
actuator; a processor coupled to haptic actuator configured to control
the operation of the at least one haptic actuator; one or more sensors
configured to sense movement of the device, wherein the processor is
configured to determine if movement of the device is attributable to
actuation of the haptic actuator and implement mitigation routines to
reduce the movement; and at least one acoustic sensor, wherein the
processor is configured to determine if actuation of the haptic actuator
generates sound at a level that exceeds a threshold and, if so, control
the operation of the haptic actuator to reduce the sound to a level below
the threshold.

22. The device of claim 21 wherein the one or more sensors comprises at
least one of an accelerometer, a gyroscope, a GPS, and a camera.

23. The device of claim 21 further comprising a haptic controller
configured to control the operation of the haptic actuator.

24. A method of reducing reverberation of a linear vibrator in an
electronic device, the method comprising: sensing movement of the device
using a sensor of the electronic device; generating a feedback signal
based on the sensed movement; providing the feedback signal via a
feedback control system to the linear vibrator, the feedback signals
reducing the movement of the linear vibrator.

25. The method of claim 24 wherein the sensor comprises an accelerometer.

Description:

[0002] Portable electronic devices such as mobile phones, media players,
smart phones, and the like often provide "silent alerts" that are
designed to catch a user's attention without providing an audible signal
from a speaker. Frequently, the silent alert is set by the user when an
audible alert would be disruptive, such as in a meeting or a theater, for
example. The silent alert allows for the user to receive notification of
some event, such as in incoming call or text, for example, discretely.
Some users may even use the silent alert as their default notification
mechanism.

[0003] Typically, the silent alert is provided by a haptic device, such as
a vibrating device, intended to allow the user to feel the activation of
the alert. There are two common vibrating devices that are currently
implemented. One includes an eccentric weight coupled to a motor driven
shaft that, when rotated, provides vibration. Another includes a linear
vibrator that rather than having rotational movement, displaces in a
linear path. The two types of vibrators present separate issues.

[0004] With regard to the rotating eccentric weight vibrator, the silent
alerts are not so silent in some instances. Specifically, for example,
when a mobile phone is set to actuate a silent alert while it is in
contact with a hard surface (e.g., on a table or a shelf, or in a
drawer), the rotating eccentric weight may cause the mobile phone to
vibrate and rattle against the surface. In some cases, the noise caused
by the rattling exceeds that of audible alerts and may be much more
disruptive. Further, the mobile phone may move along the surface when the
vibrating device is activated, thus placing the mobile phone at risk of
falling.

[0005] The linear vibrator may similarly exhibit some of the same symptoms
as the rotating eccentric weight vibrators, but perhaps not to the same
degree. The mechanical structure of the linear vibrators may also result
in their weights being displace when not actuated. In particular, when
moved in or impacted in a direction that corresponds to the direction of
linear displacement of the linear vibrator, displacement of the weight
may occur and a user may sense the displacement. In some cases, the
sensed displacement may feel spongy and/or detract from a user's
impression of quality of the device in which the linear vibrator is
implemented.

SUMMARY

[0006] One embodiment may take the form of a portable electronic device
having at least one haptic actuator and a processor coupled to haptic
actuator configured to control the operation of the at least one haptic
actuator. Additionally, the device includes one or more sensors
configured to sense movement of the device. The processor is configured
to determine if movement of the device is attributable to actuation of
the haptic actuator and implement mitigation routines to reduce the
movement if the movement is attributable to actuation of the haptic
actuator. Further, the device includes at least one acoustic sensor. The
processor is configured to determine if actuation of the haptic actuator
generates sound at a level that exceeds a threshold and, if so, control
the operation of the haptic actuator to reduce the sound to a level below
the threshold.

[0007] Another embodiment may take the form of a method of reducing noise
from vibration of a device on a hard surface. The method includes
activating a haptic device to indicate an alert and sensing an audible
level during activation of the haptic device. Additionally, the method
includes determining if the audible level exceeds a threshold and
initiating mitigation routines to reduce the audible level to a level
below the threshold if the threshold is exceeded.

[0008] Yet another embodiment may take the form of a method of mitigating
locomotion of a device due to haptic devices. The method includes
activating a haptic device and sensing movement of the device when the
haptic device is activated. Moreover, the method includes determining if
the movement is due to the haptic device activation and initiating
mitigation routines to reduce the movement of the device due to
activation of the haptic device.

[0009] Still another embodiment may take the form of a method of reducing
reverberation of a linear vibrator in an electronic device. The method
includes sensing movement of the linear vibrator and determining if the
linear vibrator is activated. If the linear vibrator is not activated,
the method also includes providing feedback signals to a feedback control
system. The feedback signals reduce the movement of the linear vibrator.

[0010] Yet another embodiment may take the form of a method of reducing
reverberation of a linear vibrator in an electronic device. The method
includes sensing movement of the device using a sensor of the electronic
device and generating a feedback signal based on the sensed movement. The
feedback signal is provided via a feedback control system to the linear
vibrator reduce the movement of the linear vibrator.

[0011] While multiple embodiments are disclosed, still other embodiments
of the present invention will become apparent to those skilled in the art
from the following Detailed Description. As will be realized, the
embodiments are capable of modifications in various aspects, all without
departing from the spirit and scope of the embodiments. Accordingly, the
drawings and detailed description are to be regarded as illustrative in
nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a block diagram illustrating an electronic device having
haptic device;

[0014] FIG. 3 is a flowchart illustrating a method for reducing noise
generated by actuation of the haptic device of the electronic device of
FIG. 1.

[0015] FIG. 4 illustrates the electronic device of FIG. 1 with visual and
audible alerts activated in lieu of a haptic alert.

[0016]FIG. 5 is a flowchart illustrating a method of mitigating haptic
device induced movement of the device.

[0017]FIG. 6 illustrates the electronic device of FIG. 1 determining that
it is near an edge.

[0018] FIG. 7 illustrates the electronic device of FIG. 1 utilizing edge
features in its environment to aid in movement determination.

[0019] FIG. 8 is a flowchart illustrating a method of mitigating movement
of a linear vibrator when the linear vibrator is not actuated.

DETAILED DESCRIPTION

[0020] Embodiments discussed herein relate to operation of haptic devices
in portable electronic devices. In particular, devices and techniques to
limiting noise generated by the operation of haptic devices are provided.
Moreover, some embodiments are directed to limiting movement of an
electronic device when haptics are operating. Further, undesirable
movement of the haptic devices is limited by monitoring and providing
feedback to haptic devices.

[0021]FIG. 1 illustrates a block diagram of an electronic device 100
having a haptic device 102. The haptic device 102 may take the form of a
vibrating device, such as a rotating vibrator, linear vibrator, or the
like. The haptic device 102 may be controlled by a haptic controller 104.
The haptic controller 104 may be implemented in hardware, software or a
combination of both and may be configured to actuate the haptic device
102 to alert a user of the occurrence of an event, such as incoming call
or a calendar item, for example. Additionally, in some embodiments, the
haptic controller 104 may be part of a feedback control system configured
to implement mitigation techniques to reduce possibly disruptive
operation of the haptic device 102, as discussed in greater detail below.

[0022] The haptic controller 104 may be in communication with a processor
106. In some embodiments, the processor 106 may function as the haptic
controller. The processor 106 may additionally be communicatively coupled
to a display 108, a data storage device 110 and a memory device 112.
Generally, the storage device 110 may take the form of one or more
storage technologies such as flash memory, magnetic disk drives, magnetic
tape drives, optical drives, and so forth. The memory device 112 may be
implemented in any form of digital random access memory (RAM) including
dynamic RAM, synchronous dynamic RAM, and so forth. Generally, the
storage device 110 may store operating instructions that are executable
by the processor 106 to provide certain functionality, such as
determining if the haptic device 102 is making noise, if the device 100
is moving, and/or if the haptic device is displaced without being
actuated. Further, the processor 106 may be configured to
implement/execute mitigation routines (e.g., programmed software
routines) stored in the storage device 110 to reduce or eliminate the
aforementioned effects.

[0023] The processor 106 may further be communicatively coupled with one
or more input/output (I/O) devices, such as an accelerometer 114, a
gyroscope 116, an antenna 118, a microphone 120, a camera or light sensor
122, a speaker 124 and/or a global positioning system 126. The processor
106 may utilize one or more of the I/O devices to determine when the
mobile device 100 is making noise or moving when the haptic device 102 is
actuated and/or to help mitigate the effects of the actuation of the
haptic device.

[0024] For example, in one embodiment, the microphone 120 may be activated
concurrently with the haptic device 102 to determine if actuation of the
haptic device creates noise and/or the accelerometer 114 and gyroscope
116 may be used to determine if the mobile device 100 is moving when the
haptic device is actuated. With respect the actuation of the haptic
device 102 creating noise, the noise generated may generally have a
particular frequency and/or amplitude range that may help facilitate the
determination by the processor that the noise is coming from the
actuation of the haptic device rather than another source. Similarly,
movement of the mobile device resulting from the actuation of the haptic
device 102 may be distinguished from other movements based on the size,
speed and direction of the movement as detected by the accelerometer 114
and gyroscope 116.

[0025] FIG. 2 illustrates the mobile device 100 on a hard surface, such as
a table 130. When the haptic device 102 is actuated, the mobile device
100 may rattle on the table 130 and generate noise. Further, the haptic
device 102 may cause the device 100 to move across the table 130, as
indicated by the arrow 132.

[0026] FIG. 3 is a flow chart illustrating an example method 140 for
reducing the noise generated by actuation of the haptic device 102.
Initially, an incoming call may be received (Block 142) and the
microphone 120 may be activated (Block 144). The haptic device 102 is
activated (Block 146) while the microphone is active. In one embodiment,
the microphone 120 may be activated before the haptic device 102 to allow
the microphone to sample sound/noise prior to actuation of the haptic
device. This sample may serve as a baseline with which sound/noise
samples taken while the haptic device is actuated may be compared. It
should be appreciated that in other embodiments, the microphone 120 may
be activated simultaneously with the actuation of the haptic device or
after actuation of the haptic device. Generally, the noise generated from
operation of the haptic device should have a distinct frequency pattern.
For example, in some embodiments, the sound generated by haptic operation
may be between approximately 300 Hz and 400 Hz. As such, this frequency
band (or other frequency band within which the haptic device generates
noise) may be determinative of the noise generated by the haptic device
and an amplitude (and/or total power) of signals within this range may be
used for noise determination.

[0027] Regardless of when the microphone is initially activated, sound
levels are detected (Block 148). The detected sound levels may be
compared with one or more thresholds (Block 150). In one embodiment, a
threshold may be a noise level that can be expected when the haptic
device is actuated if the mobile device is not on a hard surface. As
such, the threshold may be empirically determined. For example, a first
threshold may be set at a level of a minimum noise level expected when
the device is located on a hard surface as determined through
experimentation. If the sound levels do not exceed the threshold (e.g.,
do not indicate that the mobile device 100 is making noise by rattling
against a hard surface) the sound levels may continue to be detected
while the haptic device is actuated.

[0028] In still other embodiments, the threshold level may be configured
to correspond with a volume level for an audible alert. That is, if
actuation of the haptic device generates noise that exceeds the noise
level of an audible alert, the threshold has been exceeded. Hence, the
threshold may be user configurable based on the volume setting for
audible alerts. In other embodiments, the threshold may be set to a
default noise level of audible alerts.

[0029] Some embodiments may implement multiple thresholds. For example a
first threshold may be set to a minimum noise level that is expected if
the device is located on a hard surface and a second threshold may be set
to correspond to a volume setting for an audible alert. The multiple
thresholds may provide for implementation of different mitigation
routines depending on what threshold(s) are exceeded.

[0030] If the sound levels exceed the threshold, noise mitigation routines
may be initiated (Block 152). The noise mitigation routines may include
software routines that control the operation of the haptic device 102.
For example, the noise mitigation routines may slow, stop, pulse, and/or
ramp up/ramp down the speed of the haptic device 102. In one embodiment,
the mobile device 100 may be configured to determine a speed/frequency
for the haptic device 102 that is variable and configured to eliminate
periodic elements of the rattling of the device. That is, for example, a
rotational vibrator be configured to rotate a frequency destructive to
the periodic rattling of the mobile device 100. In some embodiments, the
vibrator may be slowed, pulsed, or even stopped to eliminate the rattling
of the device and the associated noise.

[0031] Once noise mitigation routines have been initiated, an operating
environment may be determined (Block 154). For example, the light sensor
122 may be used to determine if the device 100 is in a darkened room or a
lighted room. Additionally, the GPS 126 may be used to determine if the
device is in a home, office, or other location, for example. Based on the
environmental information, alternative alerts may be initiated (Block
156). For example, visual and/or audible alerts may be initiated, such as
a light may flash, the display 108 may turn on, and/or an audible alert
may be sounded.

[0032] FIG. 4 illustrates the initiation of alternative alerts for the
device 100. Specifically, for example, the display 108 may turn on to
provide a visual alert. Additionally or alternatively, the speaker 124
may sound an audible alert. As may be appreciated, the audible alert may
be quieter and more discrete than the haptic alert. Moreover, the audible
alert that is used to replace the haptic alert may be different from
those that are typically used. For example, the audible alert may be
configured to mimic the sound that the haptic alert makes when the device
is not in contact with a hard surface (e.g., a low rumble). Other types
of alerts may be implemented in other embodiments.

[0033] As mentioned above, in some cases, the vibration of the device 100
may cause the device to move. This movement of the device 100 may be
exaggerated if the surface upon which the device is located is not level.
FIG. 5 is a flowchart illustrating a method 160 for stopping the movement
of the device 100. Initially, the haptic device 102 may be actuated
(Block 162) for example as a result of an incoming call. Upon actuation
of the haptic device 102, input from the accelerometer 114 and/or the
gyroscope may be received (Block 164). In some embodiments, an
orientation of the device 100 may be determined (Block 166). The
orientation of the device may help determine if the device is on a table,
desk, shelf and so forth, or in a pocket. That is, if the device 100 is
lying flat, it is likely that it is on a table, desk, shelf, or the like,
whereas if the device is in an upright position, it is likely in a pocket
or being held. The input from the accelerometer 114 and/or gyroscope 116
may be used for orientation determination. Further, input from the
accelerometer and/or gyroscope 116 may be used for determining if the
device 100 is moving (Block 168).

[0034] If the device 100 is not moving, while the haptic device 102 is
actuated it may continue to monitor the input from the accelerometer 114
and/or gyroscope to determine if there is movement. If it is determined
that there is movement of the mobile device, it is determined if the
movement is due to the haptic device being actuated (Block 170). For
example, in some instances, the haptic device may actuate while a user of
the device 100 is moving, rather than the movement resulting from the
haptic actuation. Movement by a user may be distinguished from haptic
induced movement in a number or different ways. In particular, a movement
that was occurring before actuation of the haptic device likely would be
attributable to a user (or other source) rather than the haptic
actuation. Additionally, gross movements, such as when a mobile device is
picked-up by a user would generally indicate user caused movement, rather
than smaller, quicker movement that may be periodic may likely be
characterized as those caused by the haptic actuation. Further, migration
movement (e.g., continuous movement in a general direction) that imitates
upon actuation of the haptic device may be characterized as being from
the haptic actuation.

[0035] In some embodiments, movement thresholds may be utilized to
determine if the movement is haptic based. For example, movements less
than six inches (e.g., movement of three, two or one inch) may indicate
that the movement is likely attributable to haptic actuation. Moreover,
thresholds may be utilized to determine if the movement should be
stopped. For example, if the device moves an inch or more due to
actuation of the haptic it mitigation may be in order. In some
embodiments, if the device does not move at least a threshold distance
due to the actuation of the haptic device, mitigation routines may not be
implemented.

[0036] If the movement is not caused by actuation of the haptic device
102, the input from the accelerometer and/or gyroscope may continue to be
monitored for further movements that may be caused by the haptic
actuation. If it is determined that the movements are a result of the
haptic actuation, it may then be determined if the device is near an edge
(Block 172). The determination as to whether the device 100 is near an
edge may be implemented in one or more of a number of ways. For example,
while the device is on a surface a light sensor of the device 100
adjacent to the surface may register little or no light until a portion
of the device extends over the edge of the surface. In other embodiments,
the camera of the device may be used in a similar manner as an edge
detection device as shown in FIG. 6. In still other embodiments, a
microphone may be utilized in a similar manner.

[0037] If the device 100 is determined to be near an edge, the haptic
device may be stopped (Block 174) and alternative alerts may be initiated
(Block 178). Additionally, in some embodiments, an edge alert may be
initiated as part of the alternative alerts to alert the user to the
position of the device. If the mobile device is not near an edge,
movement mitigation routines may be implemented (Block 176) and
alternative alerts may be initiated (Block 178). The alternative alerts
may include those discussed above, as well as others.

[0038] The movement mitigation routines may include processes configured
to reduce and/or eliminate migration of the device 100 as a result of
actuation of the haptic device 102. In some embodiments, the movement
mitigation routines may include reducing the speed of the haptic device,
slowly ramping up and then stopping or ramping down the haptic device,
and so forth. In one embodiment, in particular, the haptic device may
alternate its direction of rotation. As such, the device 100 may
initially move in a first direction due to the rotation of the haptic
device and then alternately move in a second direction opposite of the
first direction due to the reverse rotation of the haptic device, thus
resulting in a net zero movement of the device. In some embodiments, the
haptic device may alternate pulsing in each direction.

[0039] Although movement of the device 100 may be determined based on
input from the accelerometer 114 and/or gyroscope 116. Input from other
devices may also be utilized to determine if the device 100 is moving.
For example, the GPS device 126 may be used to determine if the device is
moving while the haptic device 102 is actuated. Additionally, in one
embodiment, input from the camera 122 may be used to determine if the
device 100 is moving. In particular, the camera may capture multiple
images while the haptic device 102 is actuated. Edges of items in the
captured images may be discerned by edge detection software. Movement of
the edges of the items in captured images may serve as an indication of
movement of the device. Specifically, if one or more edges are found in
the images (e.g., an edge of a light 190, a corner of a wall 192, and so
forth), and the edges move greater than a threshold distance within a
specified amount of time, it may be determined that the device is moving.
In some embodiments, the threshold distance may be approximately a
distance equal to normal shaking of the device due to actuation of the
haptic device 102. Further, the period of time may be some segment of
time less than a full "ring" of the haptic device (e.g., 1/2, 1/3, 1/4,
or 1/10 of a full ring cycle for the haptic device).

[0040] Furthermore, in some embodiments, the device 100 may be configured
to implement location based learning. For example, a GPS device may be
utilized to determine the location of the device 100 and information
about that location may be stored in the device. Specifically, a first
time the device is in a particular location it may make determinations as
to whether it is on a hard surface such as a table, desk, shelf, and so
on. If so, the next time it is placed in that location it may remember it
and act accordingly. That is, if it is on a hard surface where it is at
risk of moving and or making excessive noise if a haptic device is
actuated, then the mitigation routines may be implemented including
pulsing the haptic device, ramping up the operation of the haptic device,
and/or replacing the haptic alert with a visual or audible alert.

[0041] In linear vibrators and similar devices, movement of the mobile
device may cause movement or oscillation of the weight of the vibrator.
In particular, if the device is tapped by a user in a direction that
corresponds to the direction that the weight displaces when the vibrator
operates it may provide feedback to the user that feels spongy. FIG. 8 is
a flowchart illustrating a method of actively controlling the vibrator to
help reduce or eliminate this feedback. Initially, for example, back
electromagnetic force (EMF) from the vibrator device may be detected
(Block 200). This EMF may generally be induced by movement of a magnet of
the linear vibrator generated by displacement of the weight of the
vibrator. In other embodiments, other sensors may be utilized to
determine movement of the linear vibrator. For example, an accelerometer
may be implemented for sensing movement of the linear vibrator.

[0042] When this EMF (or movement) is detected, it is determined if the
vibrator device is actuated (Block 202). This determination may simply
include determining if an alert for an incoming call, calendar item, or
the like has issued.

[0043] If the vibrator device has been actuated, then the method 198 ends
(Block 204). If the vibrator device has not be actuated, then the
amplitude and phase of the EMF signals is determined (Block 206). This
amplitude and phase of the EMF signal is used to generate a damping
signal (Block 208). Specifically, the damping signal corresponds in
amplitude and is out of phase with the detected phase signal. The
vibrator device is then actuated with the damping signal to dampen and/or
stop the movement of the vibrator (Block 210).

[0044] In another embodiment, an open-loop feedback system may be
implemented to dampen the undesired vibrations of the linear vibrator.
Specifically, vibrations/impacts, such as tapping on the device, may be
sensed and a feedback signal generated based on the sensed
vibrations/impacts. In one embodiment, an accelerometer may be used to
sense the movement of the entire device, detecting both amplitude and
direction of the movement of the device. The feedback signal corresponds
with the movement and is provided to the linear vibrator to
preempt/reduce/eliminate any vibrations in the linear vibrator caused by
the sensed impact. Hence, rather than utilizing reverberations sensed
from the linear vibrator to generate a feedback signal, readings from a
separate sensor are utilized.

[0045] The foregoing describes some example embodiments for controlling
haptic devices so that they do not generate excessive noise or move when
actuated. Although the foregoing discussion has presented specific
embodiments, persons skilled in the art will recognize that changes may
be made in form and detail without departing from the spirit and scope of
the embodiments. For example, in addition to noise level, accelerometer
and gyroscopes sensing vibration of the device, a camera or light sensor
may also be used to sense vibration. Specifically, if the camera is face
down against a surface it will generally detect little or no light, but
if the device is vibrating the level of light will increase. The increase
in light detected may be used to indicate vibration. Accordingly, the
specific embodiments described herein should be understood as examples
and not limiting the scope thereof.